It is well known in the art that human airway management requires speed and efficiency. Successful insertion of an airway maintenance device into a patient must take place within 15-20 seconds to avoid hypoxia or even death. Before an airway maintenance device can be introduced into a patient, a medical practitioner must first complete certain preparatory airway control steps focused on clearing the patient's upper airway. For an unconscious patient, airway control includes clearing the tongue and other pharyngeal tissues that often obstruct the upper airway, both the buccal cavity in the mouth and the pharyngeal cavity in the throat.
It will be understood that the supraglottic region is the area of the pharynx including and immediately above the surface of the larynx where the base of the tongue meets the structures of the larynx. The laryngeal surface lies directly above the intersection between the trachea through which air passes into the lungs and the esophagus through which food passes into the stomach. The laryngeal surface includes the perilaryngeal tissues and cartilage of the vocal cords and the epiglottis. It is the epiglottis which regulates the flow of food into the esophagus and the flow of air into the larynx through the vocal cords and laryngeal inlet. The epiglottis is usually erect to allow the flow of air into the trachea during continuous breathing. When a person swallows, the epiglottis folds down to cover the larynx to protect the trachea and prevent aspiration of liquids and solids. For proper ventilation of a patient, the epiglottis must be erect and may be raised simply by tilting the patient's head or mechanically by applying pressure with a tool placed in the vallecula, a furrow between the epiglottis and the base of the tongue.
Supraglottic airway devices consist of air tubes attached to relatively large inflatable cuffs or pliant pads which seal above the larynx in the supraglottic region of the pharynx, either against the pharyngeal wall, such as the laryngeal mask airway, or “LMA,” and the Cuffed Oropharyngeal Airway, or “COPA™.” The GO2™ airway seals on the rim of the laryngeal inlet. When sealed, the supraglottic airways allow continuous flow of gases down the tube, through the larynx, and into the trachea. Because the airway device cuff or pad must be large enough to eventually seal by filling the open space in the throat, the cuffs and pads require more space for easy passage down the throat than do the air tubes to which they are attached. Since the cuffs and pads obscure the medical practitioner's line of sight into the pharyngeal cavity, the medical practitioner inserts these airway devices blindly, relying solely upon feel to avoid obstructions. For successful insertion of these airway devices, the airway device cuff or pad must not be obstructed by the tongue and other pharyngeal tissues as the airway device passes through the mouth and throat of the patient. It is crucial to prevent the cuff or pad from being caught on the epiglottis and folded down over the trachea, thereby blocking the flow of gases.
If the airway device cuff or pad is obstructed by the tongue or other pharyngeal tissues, the cuff or pad may lodge in the nasopharyngeal vault behind the soft palate because there is not enough space for the cuff or pad to make the turn around the bend of the throat. The inflatable cuff may even become folded back upon itself, or inside out, as it passes through the throat and then has to be removed and reinserted. Accordingly, the medical practitioner strives to synchronize the preparatory clearing of the tongue and other pharyngeal tissues and the insertion of the airway maintenance device, using one hand for clearing and the other for insertion, all the while feeling for and negotiating obstructions in the upper airway.
As will be appreciated by those skilled in the art, as a supraglottic airway device is pushed past these obstructions or lodges in the nasopharyngeal vault, tissue trauma results, frequently with bleeding. It is well known that patients often complain of a post-procedural sore throat. Unfortunately, there can also be rare but serious complications such as necrosis of the uvula, reduced flow of blood to the floor of the mouth, tongue paralysis and atrophy, and vocal cord paralysis.
As will be clear to those skilled in the art, a medical practitioner must also remove and reinsert an airway device in the case of epiglottic downfolding, where the airway device pushes the epiglottis down over the laryngeal inlet, thereby blocking the flow of air through the upper airway. This proclivity toward downfolding is a particular problem with the prevalent supraglottic device, the LMA, resulting in partial or complete obstruction of the upper airway and gastric insufflation. A further difficulty can occur if a downfolded epiglottis only partially blocks the airway, wherein distention of the stomach may be the first sign of trouble. To deal with such a situation, practitioners may need to interrupt active medical procedures to allow removal and reinsertion of the airway maintenance device. Removal and reinsertion of the inserted airway device considerably slows the airway control and maintenance procedures, particularly because the danger of hypoxia and organ damage or even death during the reinsertion of the airway device usually necessitates an intermediate pause for reoxygenation of the patient with the use of a simple face mask. Meanwhile, other medical procedures are delayed while the medical team waits for successful insertion of the LMA.
Accordingly, as will be clear to those skilled in the art, a tool used to contemporaneously clear the tongue and other pharyngeal tissues from the throat and mouth and raise the epiglottis would optimize rapid proper insertion of the LMA and other supraglottic airway devices thereby minimizing tissue trauma and post-procedural patient discomfort. Forceps have been used to pull the tongue forward to the front of the mouth, and tongue-depressors have been used to compress the tongue; however, neither forceps nor a tongue-depressor is effective for clearing the tongue and other pharyngeal tissues to create space in both the pharyngeal and buccal cavities, and neither can be used to raise the epiglottis. Forceps can slip and do not compress the entire surface of the tongue. Straight blade tongue depressors are not shaped to bend around the approximately 90° angle at the top of the throat and thus cannot flatten the surface of the tongue from its base all the way up and around through the buccal cavity. The tongue could obtrude beneath and around the depressor or slip back into the pharynx. A tongue-depressor could not contemporaneously approximate the vallecula to raise the epiglottis.
For example, Nakagawa, in U.S. Pat. No. 4,996,976, discloses a disposable straight-blade tongue depressor with an optical fiber light source. Inserted deep within the pharynx, Nakagawa could not follow the back surface of the tongue but would rest at an oblique angle to the tongue.
Curved tongue depressors are similarly limited. Osborne, U.S. Pat. No. 412,409 discloses a tongue-depressing insufflator similar to the mirrored depressor familiar from doctors and dentist' offices, wherein a small curved plate is used to gently depress the back curve of the tongue at the bend in the throat. The tongue is a fleshy, muscular organ with substantial depth beneath its surface; Osborne would be incapable of forcibly compressing, lifting, and flattening the entire tongue through the pharyngeal and buccal cavities.
In U.S. Pat. No. 3,890,960, Wunsch discloses a medical diagnostic inspection spatula having a slight, flat curve configuration, however the tool is configured with two prongs at the insertion end so that only the prongs rest on the base of the tongue. Wunsch is designed for examination of an awake patient without risk of triggering the gag reflex and could not be used compress the tongue out of the pharyngeal cavity or to raise the epiglottis.
Of course, many medical practitioners resort to manually lifting the tongue forward, but this requires putting one hand into the mouth of the patient where the hand itself obstructs insertion of the airway device. Furthermore, they cannot reach around the airway device to lift the epiglottis with their fingers.
This manual technique of clearing the tongue and other pharyngeal tissues, unfortunately, places both the medical practitioner and patient at heightened risk of infection, allergic reaction, and injury. Indeed, such a manual technique creates a risk of contamination and disease for both practitioner and patient: the medical practitioner's gloved hand may introduce latex glove powder and germs into the patient's mouth; the patient's teeth and any orthodontic devices may damage the medical practitioner's glove and hand.
Practitioners in the art are conversant with laryngoscopes as airway control tools that allow a practitioner to visualize the vocal cords and raise the epiglottis for endotracheal intubation, wherein a thin tube is passed through the larynx and directly into the trachea below. However, as is known in the art, these laryngoscopic blades do not create space for the supraglottic devices which stop above the larynx. The blades merely displace the tongue sideways out of the line of sight of the medical practitioner; the blades do not compress the tongue out of the pharyngeal cavity or flatten the tongue in the buccal cavity. Laryngoscopic blades have been developed in two general types: straight blades and curved blades having a curvature greater than the curvature of the pharynx. Both types of blades would obstruct the insertion of the cuffs or pads and attached tubes of supraglottic airway devices.
For example, Schneider, in U.S. Pat. No. 5,888,195, teaches a blade which allows better visualization of the larynx by providing a adjustable curvature. Nevertheless, this blade fails to compress and coax the tongue out of the pharynx or flatten the tongue in the buccal cavity.
Haase, in U.S. Pat. No. 5,993,383, discloses a laryngoscopic blade that purports to improve tongue control during intubation, using wing sections to compress the tongue out of the line of sight.
In addition to laryngoscopic blades, there are other devices which are purported to control the tongue during anesthesia. For control of the tongue in the awake or mildly sedated as well as the unconscious patient, Flam, in U.S. Pat. No. 5,590,643 discloses an oral intubating airway with a bite block designed to keep a patient's mouth open for insertion of various medical instruments. A short C-shaped tongue retractor is attached to the bite block to hold part of the tongue forward in the mouth and out of the throat. The retractor is short to avoid triggering the gag response.
Anunta, in U.S. Pat. No. 6,003,510, tangentially addresses the problem of flattening the tongue in the buccal cavity, but not the pharyngeal cavity. Anunta discloses a thin flat tool configured with a flattened curve which is inserted after the LMA is introduced into the buccal cavity to leverage the LMA away from the posterior wall of the pharynx so that the LMA cuff does not fold back upon itself. Anunta has an optional, ancillary use to first compress the tongue within the buccal cavity before introduction of the LMA into the buccal cavity. Anunta is designed expressly for use in the buccal cavity and could not be used to clear the upper airway by compressing the tongue and raising the epiglottis.
Thus, it is clear that there is presently no device or procedure for optimizing blind insertion of a supraglottic airway device in a patient. It would be advantageous to utilize an apparatus that enables space to be created for passage of such an airway device and attached cuff or pad by compressing and coaxing the tongue upwards and forwards to the front of the mouth. Accordingly, these limitations and disadvantages of the prior art are overcome with the present invention, and improved means and techniques are provided that are useful for increasing space in the pharyngeal cavity while simultaneously flattening the tongue in the mouth, whereby space in the buccal cavity is increased. The present invention also contemplates a tool configured with a tip wide enough to approximate the vallecula and to raise the epiglottis, and to be easily removable without disturbing the position of the cuff or pad or attached air tube of a superglottic airway device, to avoid interfering with the rapid sealing of the device in the pharynx or on the larynx per se.